This research grant application proposes continuation of established headquarters at The University of Texas Cancer Center, M. D. Anderson Hospital and Tumor Institute for the administration of the National Large Bowel Cancer Project. A proposed national research plan is presented with continuation and expansion of research programs on the biology and control of large bowel cancer in seven broad areas: (1) Carcinogenesis and Epidemiology, (2) Cell Kinetics and Molecular Control of Cell Proliferation and Differentiation and Molecular Genetics, (3) Early Diagnosis, Prevention and Human Genetics, (4) Experimental-Clinical Pharmacology, (5) Immunobiology, (6) Pathological Classification and Correlation with Prognosis, and (7) Clinical Research Treatment including chemotherapy, immunotherapy, radiation therapy, surgery and multimodal therapy. Particular emphasis is placed on etiology and pathogenesis as well as clinical research treatment with the recognition that identification of high risk groups provides an important basis for reducing cancer incidence and decreased mortality. The Project will be administered by the Project Director, Associate Director (Chairman, Working Cadre and Coordinator, Scientific Program) and Working Cadre of 15 biomedical scientists responsible for the development and review of scientific programs and applications for research grants-in-aid cooperation with consultant scientists.